noun
Surya (Hindu sun god, one of the twelve devas in Shingon Buddhism)
Buddhist term referring to the sun deity Surya, adopted into the Shingon pantheon as one of the twelve devas (十二天).
See also: 十二天
日天子は十二天の一尊として、密教の曼荼羅に描かれる。
Nittenshi is depicted in esoteric Buddhist mandalas as one of the twelve devas.
noun
Archaic term for the sun; not used in modern Japanese outside of historical or literary contexts.
古い文献では、日天子が単に太陽を指すことがある。
In old texts, Nittenshi can simply refer to the sun.
太陽 is the standard modern word for 'sun', while 日天子 is an archaic or specialized Buddhist term.
From Chinese 日天子 (rìtiānzǐ), literally 'sun heavenly son', a calque of Sanskrit Sūrya. The term entered Japanese through Buddhist texts.